Function pmap_remove_pages

freebsd/amd64/amd64/pmap.c:7994–8176

* Destroy all managed, non-wired mappings in the given user-space * pmap. This pmap cannot be active on any processor besides the * caller. * * This function cannot be applied to the kernel pmap. Moreover, it * is not intended for general use. It is only to be used during * process termination. Consequently, it can be implemented in ways * that make it faster than pmap_remove(). First,

 * that eventual TLB invalidation.
 */
void
pmap_remove_pages(pmap_t pmap)
{
	pd_entry_t ptepde;
	pt_entry_t *pte, tpte;
	pt_entry_t PG_M, PG_RW, PG_V;
	struct spglist free;
	struct pv_chunklist free_chunks[PMAP_MEMDOM];
	vm_page_t m, mpte, mt;
	pv_entry_t pv;
	struct md_page *pvh;
	struct pv_chunk *pc, *npc;
	struct rwlock *lock;
	int64_t bit;
	uint64_t inuse, bitmask;
	int allfree, field, freed, i, idx;
	boolean_t superpage;
	vm_paddr_t pa;

	/*
	 * Assert that the given pmap is only active on the current
	 * CPU.  Unfortunately, we cannot block another CPU from
	 * activating the pmap while this function is executing.
	 */
	KASSERT(pmap == PCPU_GET(curpmap), ("non-current pmap %p", pmap));
#ifdef INVARIANTS
	{
		cpuset_t other_cpus;

		other_cpus = all_cpus;
		critical_enter();
		CPU_CLR(PCPU_GET(cpuid), &other_cpus);
		CPU_AND(&other_cpus, &pmap->pm_active);
		critical_exit();
		KASSERT(CPU_EMPTY(&other_cpus), ("pmap active %p", pmap));
	}
#endif

	lock = NULL;
	PG_M = pmap_modified_bit(pmap);
	PG_V = pmap_valid_bit(pmap);
	PG_RW = pmap_rw_bit(pmap);

	for (i = 0; i < PMAP_MEMDOM; i++)
		TAILQ_INIT(&free_chunks[i]);
	SLIST_INIT(&free);
	PMAP_LOCK(pmap);
	TAILQ_FOREACH_SAFE(pc, &pmap->pm_pvchunk, pc_list, npc) {
		allfree = 1;
		freed = 0;
		for (field = 0; field < _NPCM; field++) {
			inuse = ~pc->pc_map[field] & pc_freemask[field];
			while (inuse != 0) {
				bit = bsfq(inuse);
				bitmask = 1UL << bit;
				idx = field * 64 + bit;
				pv = &pc->pc_pventry[idx];
				inuse &= ~bitmask;